GLMovement VAT date

According to the client Licence, it is possible to have a GLMovement VAT date.
So, an entry can have an accounting date and a VAT date.

Also, specific behaviour can be parametered in the Options.

To resume different behaviour in the new entries, these cases :
Default: in VAT date, the same date that accounting date
Access date: the access date + one day
LVATReturn date: the company last VAT return date + one day

You can modify this default date with the go Button at the right of the date, but some verifications are done by the program:
in Default mode: VAT date can not be inferior to the accounting date
VAT date can not be inferior to the lock date
VAT must be in the active accounting period
in Lock date mode: the same verifications are done
in Last VAT return date mode: VAT date can not be inferior to the accounting date
VAT date can not be inferior to the last VAT return date
VAT must be in the active accounting period